The Greater Wisconsin Committee, a progressive issue-advocacy group based in Madison, paid for the ad, which claims "wasteful spending, excessive overtime, growing deficits" are attributed to "Sheriff David Clarke's mismanagement."

Clarke is brushing off the ad. He told WISN 12 News he's kind of flattered by it.

"I know how to work a budget. I'm efficient with the people's money, and if that's what the threat is to them, that's my strength, and that's what they have to attack, because there's nothing else to attack me on," Clarke said.

Challenger Chris Moews did not discuss the Greater Wisconsin Committee ad Friday. Campaign manager Sachin Chheda said Moews would rather stay focused on his vision for being sheriff.

Chheda did, however, say the campaign agrees with some of the content of the ad.

"There's a tremendous amount of waste in the Sheriff's Department," he said. "That money should be used to keep people safe, and make our community stronger, and it's been just incredibly mismanaged by the sheriff."

Clarke and Moews are on the ballot for the Aug. 12 Democratic primary.

DOWNLOAD IT FOR FREE AND TRACK THE WEATHER WHEREVER YOU ARE THIS WEEKEND. COMMITMENT 2014 COVERAGE NOW. THE HOT RACE FOR MILWAUKEE COUNTY SHERIFF JUST GOT HOTTER. ASK -- A NEW ATTACK AD AGAINST THE SHERIFF HIT THE AIRWAVES TODAY AND IT'S NOT COMING FROM HIS OPPONENT. WISN 12 NEWS MIKE ANDERSON REPORTS BOTH CAMPS ARE GETTING OUTSIDE MUSCLE. WASTEFUL SPENDING, EXCESSIVE OVERTIME, GROWING DEFICIT. SHERIFF DAVID CLARKE'S MISMANAGEMENT IS THREATENING OUR PUBLIC SAFETY. THIS IS THE LATEST ATTACK AD AGAINST MILWAUKEE COUNTY SHERIFF DAVID CLARKE. IT IS BLISTERING. IT DID NOT COVER HIS OPPONENT. IT IS FROM THE GREATER WISCONSIN COMMITTEE, A PROGRESSIVE ADVOCACY ORGANIZATION. THEY WERE NOT REACHABLE FOR COMMENT. THE THIRD-PARTY ORGANIZATION IS SPENDING TENS OF THOUSANDS OF DOLLARS ON ATTACK ADS IN MILWAUKEE LEADING UP TO THE AUGUST 12 ELECTION, GOING AFTER CLARK. POLITICS AS USUAL. OR CLARK IS BRUSHING OFF THE AD. I KNOW HOW TO WORK THE BUDGET. I AM EFFICIENT WITH THE PEOPLE'S MONEY. THAT IS WHAT THE THREAT IS. THAT IS MY STRENGTH. THAT IS WHAT THEY HAVE TO ATTACK. THERE IS NOTHING ELSE TO ATTACK. HIS OPPONENT, CHRIS MAYS, DID NOT WANT TO TALK ABOUT THE AD. HIS CAMPAIGN MANAGER TELLS 12 NEWS BY PHONE THAT CHRIS MAYS WAS DUE FOCUS ON HIS VISION FOR SHERIFF. THE MAYS CAMPAIGN SAID THAT IT AGREES WITH THE AD'S CONTENT. THERE IS A TREMENDOUS AMOUNT OF WASTE IN THE SHERIFF DEPARTMENT. THAT MONEY SHOULD BE USED TO KEEP PEOPLE SAFE AND MAKE OUR COMMUNITY STRONGER. IT HAS BEEN INCREDIBLY MISMANAGED BY THE SHEER. I THINK THAT IS WHAT THE FOCUS OF THIS CAMPAIGN HAS BEEN ABOUT. BOTH CAMPAIGNS SAY THEY ARE NOT SURPRISED THAT THE ADS ARE COMING FROM AN OUTSIDE GROUP. THE NATIONAL RIFLE ASSOCIATION HAS RUN ADS SUPPORTING SHERIFF CLARK. BOTH OF THE CANDIDATES ARE ON THE BALLOT. THEY TAKE 12 NEWS THAT HAVING SPENDING FROM OUTSIDE GROUPS AS A NATIONAL POLITICAL TREND.